Bees display limited acclimation capacity for heat tolerance.

Bees are essential pollinators and understanding their ability to cope with extreme temperature changes is crucial for predicting their resilience to climate change, but studies are limited. We measured the response of the critical thermal maximum (CTMax) to short-term acclimation in foragers of six bee species from the Greek island of Lesvos, which differ in body size, nesting habit, and level of sociality. We calculated the acclimation response ratio as a metric to assess acclimation capacity and tested whether bees' acclimation capacity was influenced by body size and/or CTMax. We also assessed whether CTMax increases following acute heat exposure simulating a heat wave. Average estimate of CTMax varied among species and increased with body size but did not significantly shift in response to acclimation treatment except in the sweat bee Lasioglossum malachurum. Acclimation capacity averaged 9% among species and it was not significantly associated with body size or CTMax. Similarly, the average CTMax did not increase following acute heat exposure. These results indicate that bees might have limited capacity to enhance heat tolerance via acclimation or in response to prior heat exposure, rendering them physiologically sensitive to rapid temperature changes during extreme weather events. These findings reinforce the idea that insects, like other ectotherms, generally express weak plasticity in CTMax, underscoring the critical role of behavioral thermoregulation for avoidance of extreme temperatures. Conserving and restoring native vegetation can provide bees temporary thermal refuges during extreme weather events.

Characterization Factors to Assess Land Use Impacts on Pollinator Abundance in Life Cycle Assessment.

While wild pollinators play a key role in global food production, their assessment is currently missing from the most commonly used environmental impact assessment method, Life Cycle Assessment (LCA). This is mainly due to constraints in data availability and compatibility with LCA inventories. To target this gap, relative pollinator abundance estimates were obtained with the use of a Delphi assessment, during which 25 experts, covering 16 nationalities and 45 countries of expertise, provided scores for low, typical, and high expected abundance associated with 24 land use categories. Based on these estimates, this study presents a set of globally generic characterization factors (CFs) that allows translating land use into relative impacts to wild pollinator abundance. The associated uncertainty of the CFs is presented along with an illustrative case to demonstrate the applicability in LCA studies. The CFs based on estimates that reached consensus during the Delphi assessment are recommended as readily applicable and allow key differences among land use types to be distinguished. The resulting CFs are proposed as the first step for incorporating pollinator impacts in LCA studies, exemplifying the use of expert elicitation methods as a useful tool to fill data gaps that constrain the characterization of key environmental impacts.

High species turnover and unique plant-pollinator interactions make a hyperdiverse mountain.

We studied α- and ß-diversity of pollinators, flowering plants and plant-pollinator interactions along the altitudinal gradient of Mt. Olympus, a legendary mountain and biodiversity hotspot in Central Greece. We explored 10 study sites located on the north-eastern slope of the mountain, from 327 to 2596 m a.s.l. Insect surveys were conducted once a month using hand netting (years 2013, 2014 and 2016), and they were combined with recordings of flowering plant diversity (species richness and flower cover). We then calculated α- and ß-diversity of pollinators, plants in flower and plant-pollinator interactions, and explored their demographic response along the altitudinal gradient. Alpha diversity of pollinators, plants and plant-pollinator interactions were altitude dependent; α-diversity of all pollinators, bees, non-bumblebee bees, bee flies and butterflies showed linear declines with altitude, whereas those of hoverflies and bumblebees showed unimodal patterns. Beta diversity and its turnover component of all pollinators, hoverflies, bees, bumblebees, non-bumblebee bees, butterflies and plants showed linear increases, whereas those of bee flies and of plant-pollinator interactions varied independently from the pairwise altitudinal difference. The high dissimilarity and uniqueness of pollination networks, which is probably a result of the high biodiversity and endemism of Mt. Olympus, is driven by species turnover and the formation of new interactions between new species. Contrasting to the monotonic decline of the remaining groups, the unimodal patterns of hoverfly and bumblebee α-diversity are probably the effect of a higher tolerance of these groups to high-altitude environmental conditions. Our findings highlight that the high turnover of species and of pollination interactions along the altitudinal gradient are the mainstay of hyperdiverse mountains, a fact that conveys important historical, ecological and conservational implications.

Recent fire in a Mediterranean ecosystem strengthens hoverfly populations and their interaction networks with plants.

Fire affects many critical ecological processes, including pollination, and effects of climate change on fire regimes may have profound consequences that are difficult to predict. Considerable work has examined effects of fire on pollinator diversity, but relatively few studies have examined these effects on interaction networks including those of pollinators other than bees. We examined the effects of a severe wildfire on hoverfly pollinators in a Mediterranean island system. Using data collected over 3 consecutive years at burnt and unburnt sites, we documented differences in species diversity, abundance, and functional traits, as well as hoverfly interactions with flowering plants. Hoverfly abundance and species richness peaked during the first post-fire flowering season (year 1), which coincided with the presence of many opportunistic species. Also in year 1, hoverfly pollination networks were larger, less specialized, more nested, and less modular at burnt (vs. unburnt) sites; furthermore, these networks exhibited higher phylogenetic host-plant diversity. These effects declined over the next 2 years, with burnt and unburnt sites converging in similarity to hoverfly communities and interaction networks. While data obtained over 3 years provide a clear timeline of initial post-fire recovery, we emphasize the importance of longer-term monitoring for understanding the responses of natural communities to wildfires, which are projected to become more frequent and more destructive in the future.

Intrafloral patterns of color and scent in Capparis spinosa L. and the ghosts of its selection past.

PREMISE: Capparis spinosa is a widespread charismatic plant, in which the nocturnal floral habit contrasts with the high visitation by diurnal bees and the pronounced scarcity of hawkmoths. To resolve this discrepancy and elucidate floral evolution of C. spinosa, we analyzed the intrafloral patterns of visual and olfactory cues in relation to the known sensory biases of the different visitor guilds (bees, butterflies, and hawkmoths). METHODS: We measured the intrafloral variation of scent, reflectance spectra, and colorimetric properties according to three guilds of known visitors of C. spinosa. Additionally, we sampled visitation rates using a motion-activated camera. RESULTS: Carpenter bees visited the flowers eight times more frequently than nocturnal hawkmoths, at dusk and in the following morning. Yet, the floral headspace of C. spinosa contained a typical sphingophilous scent with high emission rates of certain monoterpenes and amino-acid derived compounds. Visual cues included a special case of multisensory nectar guide and color patterns conspicuous to the visual systems of both hawkmoths and bees. CONCLUSIONS: The intrafloral patterns of sensory stimuli suggest that hawkmoths have exerted strong historical selection on C. spinosa. Our study revealed two interesting paradoxes: (a) the flowers phenotypically biased towards the more inconsistent pollinator; and (b) floral display demands an abundance of resources that seems maladaptive in the habitats of C. spinosa. The transition to a binary pollination system accommodating large bees has not required phenotypic changes, owing to specific eco-physiological adaptations, unrelated to pollination, which make this plant an unusual case in pollination ecology.

The effect of natural disturbances on forest biodiversity: an ecological synthesis.

Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human-induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land-use change. Conversely, the suppression of natural disturbances threatens disturbance-dependent biota. Using a meta-analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α-diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground-dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α-diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta-analysis by applying a unified diversity concept based on Hill numbers to estimate α-diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity-disturbance relationships are shaped by species relative abundances. Our synthesis of α-diversity was extended by a synthesis of disturbance-induced change in species assemblages, and revealed that disturbance changes the ß-diversity of multiple taxonomic groups, including some groups that were not affected at the α-diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α-diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.

Phenology and production of pollen, nectar, and sugar in 1612 plant species from various environments.

To predict the quantity and quality of food available to pollinators in various landscapes over time, it is necessary to collect detailed data on the pollen, nectar, and sugar production per unit area and the flowering phenology of plants. Similar data are needed to estimate the contribution of plants to the functioning of food webs via the flow of energy and nutrients through the soil-plant-nectar/pollen-consumer pathway. Current knowledge on this topic is fragmented. This database represents the first compilation of data on the various food resources produced by 1612 plant species belonging to 755 genera and 133 families, including crop plants and wild plants, annuals and perennials, animal- and wind-pollinated plants, and weeds and trees growing in different ecosystems under various environmental conditions. The data set consists of 103 parameters related to the traits of plant species and geographical and environmental factors, allowing for precise calculations of the amounts of nectar, pollen, and energy provided by plants and available to consumers in the considered flora or ecosystem on a daily basis throughout the year. These parameters, gathered by us and extracted from the available literature, describe pollen, nectar, and sugar production (where applicable, in mass, volume, and concentration units), honey yield, the timing and duration of flowering, flower longevity, number of plants and flowers per unit area, weather conditions (temperature and precipitation), geographical location, landscape, and syntaxonomy. The data were obtained from various, mostly European, pedoclimatic zones, and the majority of the data were available for plant species and communities present in Central Europe, especially in Poland, where research on floral resources has a long tradition. These data are representative of the whole continent and may be used as a reference for plant communities occurring on continents other than Europe since the database allows for the consideration of differences in the production of resources by a single plant species growing in different communities. This data set provides a unique opportunity to test hypotheses related to the functioning of food webs, nutrient cycling, plant ecology, and pollinator ecology and conservation. The data are released under a CC-BY-NC-SA license, and this paper must be properly cited when using the database.

Assessing Climate Change Impacts on Island Bees: The Aegean Archipelago.

Pollinators' climate change impact assessments focus mainly on mainland regions. Thus, we are unaware how island species might fare in a rapidly changing world. This is even more pressing in the Mediterranean Basin, a global biodiversity hotspot. In Greece, a regional pollinator hotspot, climate change research is in its infancy and the insect Wallacean shortfall still remains unaddressed. In a species distribution modelling framework, we used the most comprehensive occurrence database for bees in Greece to locate the bee species richness hotspots in the Aegean, and investigated whether these might shift in the future due to climate change and assessed the Natura 2000 protected areas network effectiveness. Range contractions are anticipated for most taxa, becoming more prominent over time. Species richness hotspots are currently located in the NE Aegean and in highly disturbed sites. They will shift both altitudinally and latitudinally in the future. A small proportion of these hotspots are currently included in the Natura 2000 protected areas network and this proportion is projected to decrease in the coming decades. There is likely an extinction debt present in the Aegean bee communities that could result to pollination network collapse. There is a substantial conservation gap in Greece regarding bees and a critical re-assessment of the established Greek protected areas network is needed, focusing on areas identified as bee diversity hotspots over time.

In search of traces of the mandrake myth: the historical, and ethnobotanical roots of its vernacular names.

BACKGROUND: Mandrake (Mandragora spp.) is one of the most famous medicinal plant in western cultures since Biblical times and throughout written history. In many cultures, mandrake is related to magic and witchcraft, which is said to have a psychosomatic effect (especially when mandrake contains narcotic compounds) in addition to the pharmacological influence, as occurs with other narcotic magical plants. Due to its unique properties and related myths, it is not surprising that this plant has many names in many languages. METHODS: This paper presents an attempt to reconstruct the historical, ethnobotanical, and folkloristic roots of 292 vernacular names of Mandragora spp. in forty-one languages. We used the plant's morphological data, philology, myths and legends, medicinal properties and uses, as well as historical evidence and folkloric data, to explain meaning, origin, migration, and history of the plant's names. RESULTS: The names were classified into the following main categories: Derivatives of mandragora (19 languages), alraun (7) and of yabroukh (5). The salient groups of the plant's vernacular names are related to: Anthropomorphism (33 names in 13 languages); Similarity to other plants (28/9); Supernatural agents (28/9); Narcotic effects (21/8); Leaves, fruits, and seeds (21/8); Aphrodisiac properties (17/10); Use of a dog (15/9); Gallows (14/5); Black magic, sorcery, witchcraft (13/8), and Medicinal use (11/7). CONCLUSIONS: This frequency distribution of the mandrake's vernacular names reflects its widespread reputation as related to the doctrine of signatures, beliefs in its supernatural, natural, and mythic powers, and to a lesser extent, its uses in magic and medicine. A spatiotemporal analysis of the mandrake's names supports the old idea that the pulling ceremonies for this plant originated in the Near East and that various other myths related to this plant may have originated in different places and periods.

Three new hoverfly species from Greece (Diptera: Syrphidae).

An ongoing investigation on the Greek hoverfly fauna using adult morphology has revealed new species within three genera. In this study, the knowledge of the Mediterranean hoverfly fauna has been enhanced by describing the following species: Cheilosia candida Vujic et Radenkovic sp. n. (Pindos Mountains), Paragus thracusi Radenkovic, Likov et Vujic sp. n. (Rhodope Mountains) and Psilota aegeae Vujic, Ståhls et Smit sp. n. (Lesvos island). Diagnosis of new species, as well as identification keys to the Mediterranean species of the subgenus Convocheila Barkalov of Cheilosia Meigen and the European species of the genus Psilota Meigen have been provided. Additionally, mtDNA COI barcodes for the members of the Psilota atra group (except Psilota nana Smit et Vujic) have been given. In addition, the taxonomic status of Psilota anthracina Meigen has been discussed.

From bioaccumulation to biodecumulation: Nickel movement from Odontarrhena lesbiaca (Brassicaceae) individuals into consumers.

Hyperaccumulation describes plants' ability to take up high amounts of soil metals such as Ni and allocate them to aboveground tissues. Little is known, however, about the rate at which Ni is allocated to different plant parts, or about the consumers related to these parts, including their pollinator mutualists. In this study, we examine the interface between the serpentine endemic Ni-hyperaccumulator Odontarrhena lesbiaca and its consumers of different plant parts: leaves (consumers), floral parts (consumers and primitive pollinators), and floral rewards (true pollinators). The study was conducted at two serpentine areas on Lesvos, Greece. Over 13 rounds of sampling during the flowering period of O. lesbiaca in both areas we collected plant stems with flowers, consumers of different plant parts, and flower visitors. Collected animals were mainly insects and some spiders. Chemical analyses showed negligible Ni-concentration differences between the two areas. Among all plant parts, the lowest Ni concentration was found in pollen and the highest in leaves. Regarding animal dietary habits, folivores accumulated the highest Ni concentrations, therefore characterized as "high-Ni insects", while floral-reward consumers, both primary (bees) and secondary (Eristalis tenax, Pygopleurus spp., and wasps), bore low Ni loads. Ni-body load of predators that fed on animals that were passing by was also low. Among floral-reward consumers, short-range fliers (bees of the genera Andrena and Lasioglossum) accumulated higher Ni loads than long-range fliers (Apis mellifera, Bombus terrestris, Eristalis tenax). Solitary Andrena bees accumulated higher Ni concentration than eusocial honeybees (Apis mellifera) and bumblebees (Bombus terrestris); a group of Lasioglossum specimens encompassing both solitary and eusocial bees lay in between. Our results show that diet, foraging distance, and sociality are important factors for Ni transferred into consumers and mutualists, mostly insects that are directly associated with different plant parts of O. lesbiaca.

A critical analysis of the potential for EU Common Agricultural Policy measures to support wild pollinators on farmland.

Agricultural intensification and associated loss of high-quality habitats are key drivers of insect pollinator declines. With the aim of decreasing the environmental impact of agriculture, the 2014 EU Common Agricultural Policy (CAP) defined a set of habitat and landscape features (Ecological Focus Areas: EFAs) farmers could select from as a requirement to receive basic farm payments. To inform the post-2020 CAP, we performed a European-scale evaluation to determine how different EFA options vary in their potential to support insect pollinators under standard and pollinator-friendly management, as well as the extent of farmer uptake.A structured Delphi elicitation process engaged 22 experts from 18 European countries to evaluate EFAs options. By considering life cycle requirements of key pollinating taxa (i.e. bumble bees, solitary bees and hoverflies), each option was evaluated for its potential to provide forage, bee nesting sites and hoverfly larval resources.EFA options varied substantially in the resources they were perceived to provide and their effectiveness varied geographically and temporally. For example, field margins provide relatively good forage throughout the season in Southern and Eastern Europe but lacked early-season forage in Northern and Western Europe. Under standard management, no single EFA option achieved high scores across resource categories and a scarcity of late season forage was perceived.Experts identified substantial opportunities to improve habitat quality by adopting pollinator-friendly management. Improving management alone was, however, unlikely to ensure that all pollinator resource requirements were met. Our analyses suggest that a combination of poor management, differences in the inherent pollinator habitat quality and uptake bias towards catch crops and nitrogen-fixing crops severely limit the potential of EFAs to support pollinators in European agricultural landscapes. Policy Implications. To conserve pollinators and help protect pollination services, our expert elicitation highlights the need to create a variety of interconnected, well-managed habitats that complement each other in the resources they offer. To achieve this the Common Agricultural Policy post-2020 should take a holistic view to implementation that integrates the different delivery vehicles aimed at protecting biodiversity (e.g. enhanced conditionality, eco-schemes and agri-environment and climate measures). To improve habitat quality we recommend an effective monitoring framework with target-orientated indicators and to facilitate the spatial targeting of options collaboration between land managers should be incentivised.

La intensificación agrícola y la consecuente pérdida de hábitats de alta calidad son desencadenantes clave del declive de los insectos polinizadores. Con el objetivo de disminuir el impacto ambiental de la agricultura, la Política Agrícola Común (PAC) de la UE de 2014 definió un conjunto de medidas para hábitats y paisajes (Áreas de Enfoque Ecológico: EFA por sus siglas en inglés) que los agricultores podían seleccionar como requisito para recibir pagos agrícolas básicos. Para informar la reforma de la PAC a partir a 2020, realizamos una evaluación a escala europea para determinar cómo las diferentes opciones de EFA varían en su potencial para asistir a los insectos polinizadores bajo un manejo estándar y amigable con los polinizadores, así como su aceptación por parte de los agricultores.El proceso estructurado de elicitación Delphi para evaluar las opciones de EFA involucró a 22 expertos de 18 países europeos. Se consideraron los requisitos de los diferentes taxones de polinizadores (es decir, abejorros, abejas solitarias y sírfidos) evaluando cada opción por su potencial para proporcionar forraje, sitios de nidificación y recursos para las larvas.Las opciones de EFA variaron sustancialmente en la cantidad de recursos que se percibía que proporcionan y su efectividad vario geográfica y temporalmente. Por ejemplo, los márgenes de cultivos proporcionan un forraje relativamente bueno durante toda la temporada en el sur y el este de Europa, pero carecen de forraje a principios de temporada en el norte y oeste de Europa. Bajo el manejo estándar, ninguna opción de EFA logró puntuaciones altas en todas las categorías de recursos y en general se percibió una escasez de forraje al final de la temporada.Los expertos identificaron oportunidades sustanciales para mejorar la calidad del hábitat mediante la adopción de un manejo amigable con los polinizadores. Sin embargo, mejorar la gestión por sí solo es poco probable que garantice que se cumplan todos los requisitos necesarios para los polinizadores. Nuestro análisis sugiere que una combinación de manejo inadecuado, diferencias de calidad inherentes a los distintos hábitat y el sesgo de aceptación hacia cultivos de cobertura y cultivos que fijan nitrógeno limitan severamente el potencial de los EFA para apoyar a los polinizadores en los paisajes agrícolas europeos. Implicaciones políticas. Para conservar a los polinizadores y ayudar a proteger los servicios de polinización, nuestro estudio destaca la necesidad de crear una variedad de hábitats interconectados y bien administrados que se complementen entre sí en los recursos que ofrecen. Para lograr esto, la PAC post­2020 debe integrar los diferentes vehículos de implementación destinados a proteger la biodiversidad (por ejemplo, condicionalidad mejorada, esquemas ecológicos y medidas agroambientales y climáticas). Para mejorar la calidad del hábitat, recomendamos un marco de monitoreo efectivo con indicadores orientados a objetivos y incentivar la colaboración entre los administradores de las tierras.

L'intensification agricole et la perte associée d'habitats semi­naturels sont les principaux moteurs du déclin des insectes pollinisateurs. Dans l'intention de réduire l'impact environnemental de l'agriculture, la politique agricole commune (PAC) de l'UE de 2014 a défini un ensemble d'habitats et d'éléments paysagers (surfaces d'intérêt écologique: SIE) dans la mise en place ou le respect desquels les agriculteurs pouvaient s'engager comme condition pour bénéficier d'aides économiques européennes (droit au paiement de base). Pour éclairer la PAC post­2020, nous avons évalué à l'échelle européenne et à dire d'expert, d'une part les potentialités des diverses SIE à favoriser les insectes pollinisateurs, via une gestion standard et via une gestion optimisée, et d'autre part l'étendue de l'adoption de ces mesures par les agriculteurs.Un processus structuré d'élaboration et d'agrégation des opinions (méthode Delphi) a fait appel à 22 experts de 18 pays européens pour évaluer les potentialités des diverses SIE. Considérant les traits bioécologiques des principaux taxons pollinisateurs (i.e. bourdons, abeilles solitaires et syrphes), chaque SIE a été évaluée pour son potentiel à fournir des ressources trophiques et des sites de reproduction (sites de nidification pour les bourdons et abeilles, sites de ponte et développement larvaire pour les syrphes).Les SIE différaient considérablement les unes des autres sur les ressources qu'elles étaient censées offrir et leur efficacité variait géographiquement et temporellement. Par exemple, les bords de champ peuvent fournir des ressources trophiques tout au long de l'année en Europe du Sud et de l'Est mais pas en début de saison en Europe du Nord et de l'Ouest. En cas de gestion standard, aucun type de SIE n'atteint de score élevé pour aucun type de ressource, et une période de disette alimentaire survient en fin de saison.Les experts ont mis en évidence de possibles et substantielles améliorations des SIE par le biais de leur gestion optimisée. Cependant, cette seule amélioration ne garantit pas la fourniture de ressources suffisantes aux pollinisateurs des paysages agricoles européens. Pour cela, des habitats spécifiques doivent être favorisés, dont la mise en place ne doit pas être entravée par un choix massif de SIE à base de cultures intermédiaires pièges à nitrates ou fixatrices d'azote. Implications politiques. Pour préserver les pollinisateurs et le service de pollinisation des plantes entomophiles, notre étude souligne la nécessité de créer une diversité d'habitats interconnectés, gérés de façon optimale, qui se complètent mutuellement dans les ressources qu'ils offrent. Pour atteindre cet objectif, la PAC post­2020 doit adopter une vision holistique de la mise en œuvre des différents leviers de protection de la biodiversité (e.g. éco­conditionnalité renforcée, programmes verts ou 'eco­schemes', mesures agro­environnementales et climatiques). Pour réellement améliorer la qualité des habitats, nous recommandons des suivis efficaces de la biodiversité à l'aide d'indicateurs pertinents. Enfin, pour optimiser la disposition spatiale des SIE et leur connectivité, la collaboration entre les différents gestionnaires des espaces agricoles doit être encouragée.

A intensificação agrícola e a perda associada de habitats de elevada qualidade são os principais factores que impulsionam o declínio dos insetos polinizadores. A fim de mitigar o impacto ambiental da agricultura, a Política Agrícola Comum (PAC) da UE, de 2014, definiu um conjunto de atributos ou estruturas do habitat e da paisagem, designadas de Áreas Foco Ecológico (AFEs) que devem ser mantidas pelos agricultores como requisito para obter as ajudas económicas previstas nas medidas agroambientais. No presente trabalho realizamos uma avaliação à escala europeia das diferentes opções destas estruturas, a fim de munir a PAC pós­2020, com informação sobre a importância das AFEs. Estas variam muito quanto ao seu potencial no apoio às populações de polinizadores, de acordo com a extensão da sua aceitação pelos agricultores e das práticas adoptadas por estes na sua gestão, que podem consistir em práticas padrão ou práticas mais amigáveis para os polinizadores.Um processo estruturado, com base na técnica de elicitação de Delphi foi desenvolvido, envolvendo 22 especialistas de 18 países europeus, com o objectivo de avaliar as opções de AFEs previstas na PAC. Esta avaliação levou em consideração os requisitos do ciclo de vida dos taxa dos principais polinizadores, ou seja, as abelhas, as abelhas solitárias e os sirfídeos ou moscas­das­flores. Cada AFE foi avaliada quanto ao seu potencial para fornecer alimento, locais de nidificação, e recursos para as larvas dos sirfídeos.A percepção quanto à eficácia das AFEs como fonte de recursos (alimento) para os polinizadores variou substancialmente, do ponto de vista quer geográfico, quer temporal (época do ano). Por exemplo, a AFE, faixas verdes nas margens do campo são consideradas uma boa fonte de alimento, no sul e leste da Europa, durante todo ano, mas ineficazes, no norte e oeste da Europa, no início do ano. Nenhuma EFA alcançou pontuações elevadas na categoria de recursos (fonte de alimento), quando submetida ao maneio padrão, sendo consideradas ineficientes, na segunda metade do ano.Os especialistas envolvidos identificaram oportunidades de melhoria substancial na qualidade do habitat, através da adopção de práticas de maneio das EFAs mais "amigáveis" para com os polinizadores. No entanto, a melhoria das práticas de maneio das EFAs por si só, dificilmente garantirá todos os requisitos necessários para a manutenção das populações de polinizadores. A nossa avaliação sugere que a combinação de práticas de má gestão (maneio), diferenças inerentes à qualidade do habitat dos polinizadores e o aumento do bias que resulta da utilização de espécies de crescimento rápido ou fixadoras de azoto limitam severamente o papel e potencial destas estruturas na manutenção das populações de polinizadores nas paisagens agrícolas europeias. Implicações políticas. A conservação dos polinizadores ajuda a proteger os serviços de polinização providenciados por estes. O nosso estudo destaca a necessidade de criar uma variedade de habitats interconectados e geridos de forma que se complementem na oferta de recursos (alimento, locais de nidificação e recursos para as larvas) aos polinizadores. Para atingir este objectivo, a PAC pós­2020 deve adoptar uma visão holística na implementação das EFAs, que integre os diferentes programas destinados a protecção da biodiversidade (por exemplo, maior condicionalidade, esquemas ecológicos, e medidas agroambientais e de adaptação climática). Para melhorar a qualidade do habitat, recomendamos uma estrutura de monitorização eficaz suportada por indicadores quantitativos e qualitativos orientados para metas, que permitam facilitar a tomada de decisões direcionadas especificamente para as EFAs, e que a colaboração entre os gestores da terra (agricultores) seja incentivada.

The wild bees (Hymenoptera, Apoidea) of the island of Cyprus.

Cyprus, the third largest island in the Mediterranean, constitutes a biodiversity hotspot with high rates of plant endemism. The wild bees of the island were studied extensively by the native George Mavromoustakis, a world-renowned bee taxonomist, who collected extensively on the island from 1916 to 1957 and summarised his results in a series of eight Cyprus-specific papers published from 1949 ["1948"] to 1957. The current work represents the first modern checklist of the wild bees of Cyprus, based on a compilation of previous publications, museum specimens and authors' recent collections. Overall, 369 verified wild bee species have been recorded on the island, with eleven species reported from Cyprus for the first time. The island hosts all six of the globally widespread bee families, with Apidae represented by 110 species, Megachilidae with 91, Andrenidae with 76, Halictidae with 72, Colletidae with 19, and Melittidae with 1. Twenty-one of the recorded bee species are endemic (i.e., 5.7 % endemism rate) and Cyprus ranks third after Lesvos and Sicily in known bee species richness among the Mediterranean islands. Previously unpublished records from various locations on Cyprus for 156 previously reported bee species are also provided in the study. The current work provides a baseline for future studies of wild bee diversity on the island of Cyprus and neighbouring regions.

Moderate fire severity is best for the diversity of most of the pollinator guilds in Mediterranean pine forests.

Fire, a frequent disturbance in the Mediterranean, affects pollinator communities. We explored the response of major pollinator guilds to fire severity, across a fire-severity gradient at different spatial scales. We show that the abundance of all pollinator groups responded to fire severity, and that bees and beetles showed in addition a significant species-diversity response. Bees, sawflies, and wasps responded to fire severity at relatively small spatial scales (250-300 m), whereas flies and beetles responded at larger spatial scales. The response of bees, sawflies, and wasps was unimodal, as predicted by the intermediate disturbance hypothesis, whereas flies and beetles showed a negative response. A possible explanation is that the observed patterns (spatial scale and type of response) are driven by taxa-specific ecological and life-history traits, such as nesting preference and body size, as well as the availability of resources in the postfire landscape. Our observational study provides an insight into the effect of fire severity on pollinators. However, future research exploring the explicit link between the pre- and postfire landscape structure and pollinator traits and responses is required for further establishment and understanding of cause-effect relationships.

Phenology determines the robustness of plant-pollinator networks.

Plant-pollinator systems are essential for ecosystem functioning, which calls for an understanding of the determinants of their robustness to environmental threats. Previous studies considering such robustness have focused mostly on species' connectivity properties, particularly their degree. We hypothesized that species' phenological attributes are at least as important as degree as determinants of network robustness. To test this, we combined dynamic modeling, computer simulation and analysis of data from 12 plant-pollinator networks with detailed information of topology of interactions as well as species' phenology of plant flowering and pollinator emergence. We found that phenological attributes are strong determinants of network robustness, a result consistent across the networks studied. Plant species persistence was most sensitive to increased larval mortality of pollinators that start earlier or finish later in the season. Pollinator persistence was especially sensitive to decreased visitation rates and increased larval mortality of specialists. Our findings suggest that seasonality of climatic events and anthropic impacts such as the release of pollutants is critical for the future integrity of terrestrial biodiversity.

Differential Effects of Climate Warming on the Nectar Secretion of Early- and Late-Flowering Mediterranean Plants.

Floral nectar is a vital resource for pollinators, thus having a very important role in ecosystem functioning. Ongoing climate warming could have a negative effect on nectar secretion, particularly in the Mediterranean, where a strong temperature rise is expected. In turn, decreased nectar secretion, together with shifts in flowering phenology can disrupt plant-pollinator interactions and consequently affect the entire ecosystem. Under fully controlled conditions, we tested how temperature influenced nectar secretion (through nectar volume, sugar concentration, sugar content, and number of flowers produced) in six Mediterranean plant species flowering from winter to summer (viz. Asphodelus ramosus, Ballota acetabulosa, Echium plantagineum, Lavandula stoechas, Rosmarinus officinalis, and Teucrium divaricatum). We compared the changes in nectar secretion under temperatures expected by the end of the century and estimated the effect of climate warming on nectar secretion of plants flowering in different seasons. We found a significant effect of temperature on nectar secretion, with a negative effect of very high temperatures in all species. Optimal temperatures for nectar secretion were similar to the mean temperatures in the recent past (1958-2001) during the respective flowering time of each species. Increasing temperatures, however, will affect differently the early-flowering (blooming in winter and early spring) and late-flowering species (blooming in late spring and early summer). Temperature rise expected by the end of the century will shift the average temperature beyond the optimal range for flower production and the sugar produced per plant in late-flowering species. Therefore, we expect a future decrease in nectar secretion of late-flowering species, which could reduce the amount of nectar resources available for their pollinators. Early-flowering plants will be less affected (optimal temperatures were not significantly different from the future projected temperatures), and may in some cases even benefit from rising temperatures. However, as many earlier studies have found that early-flowering species are more prone to shifts in phenology, the plant-pollinator interactions could instead become affected in a different manner. Consequently, climate warming will likely have a distinctive effect on both plant and pollinator populations and their interactions across different seasons.

Disentangling the role of floral sensory stimuli in pollination networks.

Despite progress in understanding pollination network structure, the functional roles of floral sensory stimuli (visual, olfactory) have never been addressed comprehensively in a community context, even though such traits are known to mediate plant-pollinator interactions. Here, we use a comprehensive dataset of floral traits and a novel dynamic data-pooling methodology to explore the impacts of floral sensory diversity on the structure of a pollination network in a Mediterranean scrubland. Our approach tracks transitions in the network behaviour of each plant species throughout its flowering period and, despite dynamism in visitor composition, reveals significant links to floral scent, and/or colour as perceived by pollinators. Having accounted for floral phenology, abundance and phylogeny, the persistent association between floral sensory traits and visitor guilds supports a deeper role for sensory bias and diffuse coevolution in structuring plant-pollinator networks. This knowledge of floral sensory diversity, by identifying the most influential phenotypes, could help prioritize efforts for plant-pollinator community restoration.

Landscape spatial configuration is a key driver of wild bee demographics.

The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated by seminatural habitats, such as the islands of the Aegean Archipelago. In addition, research so far has focused on the landscape impacts on bees sampled in cropped fields while the landscape effects on bees inhabiting seminatural habitats are understudied. Here, we investigate the impact of the landscape on wild bee assemblages in 66 phryganic (low scrubland) communities on 8 Aegean islands. We computed landscape metrics (total area and total perimeter-area ratio) in 4 concentric circles (250, 500, 750, and 1000 m) around the center of each bee sampling site including 3 habitat groups (namely phrygana, cultivated land, and natural forests). We further measured the local flower cover in 25 quadrats distributed randomly at the center of each sampling site. We found that the landscape scale is more important than the local scale in shaping abundance and species richness of bees. Furthermore, habitat configuration was more important than the total area of habitats, probably because it affects bees' movement across the landscape. Phrygana and natural forests had a positive effect on bee demographics, while cultivated land had a negative effect. This demonstrates that phryganic specialists drive bee assemblages in these seminatural landscapes. This finding, together with the shown importance of landscape scale, should be considered for the management of wild bees with special emphasis placed on the spatial configuration of seminatural habitats.

Community-wide integration of floral colour and scent in a Mediterranean scrubland.

Angiosperm flowers have evolved a dazzling palette of colours and a rich bouquet of scents, principally serving to attract pollinators. Despite recent progress in the ecology of pollination, the sensory floral traits that are important for communication with pollinators (for example, colour and scent) have not been assessed in an unbiased, integrative sense within a community context. Nonetheless, floral sensory stimuli are known key factors that mediate flower visitation, thus affecting community dynamics. Here we show that flowers of the phrygana, a natural Mediterranean scrubland, display integrated patterns of scent composition and colour (as perceived by pollinators). Surprisingly, the data reveal predictive relationships between patterns of volatile composition and flower reflectance spectra. The presence of nectar is related to visual cues and the qualitative composition of floral aromas. Our results reveal a coordinated phenotypic integration consistent with the sensory abilities and perceptual biases of bees, suggesting potential facilitative effects for pollination and highlighting the fundamental importance of bees in Mediterranean-type ecosystems. We offer our unbiased approach as a starting point for more extensive, global investigations of the diversity of floral sensory phenotypes and its role in the community ecology of plant-pollinator interactions.

Self-compatibility is over-represented on islands.

Because establishing a new population often depends critically on finding mates, individuals capable of uniparental reproduction may have a colonization advantage. Accordingly, there should be an over-representation of colonizing species in which individuals can reproduce without a mate, particularly in isolated locales such as oceanic islands. Despite the intuitive appeal of this colonization filter hypothesis (known as Baker's law), more than six decades of analyses have yielded mixed findings. We assembled a dataset of island and mainland plant breeding systems, focusing on the presence or absence of self-incompatibility. Because this trait enforces outcrossing and is unlikely to re-evolve on short timescales if it is lost, breeding system is especially likely to reflect the colonization filter. We found significantly more self-compatible species on islands than mainlands across a sample of > 1500 species from three widely distributed flowering plant families (Asteraceae, Brassicaceae and Solanaceae). Overall, 66% of island species were self-compatible, compared with 41% of mainland species. Our results demonstrate that the presence or absence of self-incompatibility has strong explanatory power for plant geographical patterns. Island floras around the world thus reflect the role of a key reproductive trait in filtering potential colonizing species in these three plant families.